Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

On Mon, 2014-11-10 at 16:42 +, David Vrabel wrote: > On 10/11/14 16:39, Zoltan Kiss wrote: > > > > The BUG_ON suggested by Stefan would be still reasonable: > > > > BUG_ON(((page-compound_head(page))*PAGE_SIZE)+offset+len > > > PAGE_SIZE< > Well, it wouldn't trigger but I don't think it is u

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

On 10/11/14 16:39, Zoltan Kiss wrote: > > The BUG_ON suggested by Stefan would be still reasonable: > > BUG_ON(((page-compound_head(page))*PAGE_SIZE)+offset+len > > PAGE_SIZE

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

On 10/11/14 14:41, David Vrabel wrote: On 10/11/14 14:35, Seth Forshee wrote: On Fri, Nov 07, 2014 at 10:44:15AM +, David Vrabel wrote: On 06/11/14 21:49, Seth Forshee wrote: We've had several reports of hitting the following BUG_ON in xennet_make_frags with 3.2 and 3.13 kernels (I'm cur

Re: BUG in xennet_make_frags with paged skb data

On 10/11/14 14:35, Seth Forshee wrote: > On Fri, Nov 07, 2014 at 10:44:15AM +, David Vrabel wrote: >> On 06/11/14 21:49, Seth Forshee wrote: >>> We've had several reports of hitting the following BUG_ON in >>> xennet_make_frags with 3.2 and 3.13 kernels (I'm currently awaiting >>> results of te

Re: BUG in xennet_make_frags with paged skb data

On Fri, Nov 07, 2014 at 10:44:15AM +, David Vrabel wrote: > On 06/11/14 21:49, Seth Forshee wrote: > > We've had several reports of hitting the following BUG_ON in > > xennet_make_frags with 3.2 and 3.13 kernels (I'm currently awaiting > > results of testing with 3.17): > > > > /* Gran

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

Hi, On 07/11/14 11:08, Stefan Bader wrote: On 07.11.2014 11:44, David Vrabel wrote: On 06/11/14 21:49, Seth Forshee wrote: We've had several reports of hitting the following BUG_ON in xennet_make_frags with 3.2 and 3.13 kernels (I'm currently awaiting results of testing with 3.17): /

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

On 07.11.2014 13:21, Zoltan Kiss wrote: > > > On 07/11/14 12:15, Stefan Bader wrote: >> On 07.11.2014 12:22, Eric Dumazet wrote: >>> On Fri, 2014-11-07 at 09:25 +, Zoltan Kiss wrote: >>> >>> Please do not top post. >>> Hi, AFAIK in this scenario your skb frag is wrong. The page

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

On 07/11/14 12:15, Stefan Bader wrote: On 07.11.2014 12:22, Eric Dumazet wrote: On Fri, 2014-11-07 at 09:25 +, Zoltan Kiss wrote: Please do not top post. Hi, AFAIK in this scenario your skb frag is wrong. The page pointer should point to the original compound page (not a member of it),

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

On 07.11.2014 12:22, Eric Dumazet wrote: > On Fri, 2014-11-07 at 09:25 +, Zoltan Kiss wrote: > > Please do not top post. > >> Hi, >> >> AFAIK in this scenario your skb frag is wrong. The page pointer should >> point to the original compound page (not a member of it), and offset >> should be

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

On Fri, 2014-11-07 at 09:25 +, Zoltan Kiss wrote: Please do not top post. > Hi, > > AFAIK in this scenario your skb frag is wrong. The page pointer should > point to the original compound page (not a member of it), and offset > should be set accordingly. > For example, if your compound pag

Re: BUG in xennet_make_frags with paged skb data

On 07.11.2014 11:44, David Vrabel wrote: > On 06/11/14 21:49, Seth Forshee wrote: >> We've had several reports of hitting the following BUG_ON in >> xennet_make_frags with 3.2 and 3.13 kernels (I'm currently awaiting >> results of testing with 3.17): >> >> /* Grant backend access to each sk

Re: BUG in xennet_make_frags with paged skb data

On 06/11/14 21:49, Seth Forshee wrote: > We've had several reports of hitting the following BUG_ON in > xennet_make_frags with 3.2 and 3.13 kernels (I'm currently awaiting > results of testing with 3.17): > > /* Grant backend access to each skb fragment page. */ > for (i = 0; i < f

Re: [Xen-devel] BUG in xennet_make_frags with paged skb data

Hi, AFAIK in this scenario your skb frag is wrong. The page pointer should point to the original compound page (not a member of it), and offset should be set accordingly. For example, if your compound page is 16K (4 page), then the page pointer should point to the first page, and if the data s

BUG in xennet_make_frags with paged skb data

We've had several reports of hitting the following BUG_ON in xennet_make_frags with 3.2 and 3.13 kernels (I'm currently awaiting results of testing with 3.17): /* Grant backend access to each skb fragment page. */ for (i = 0; i < frags; i++) { skb_frag_t *frag = skb